Even in a moment of triumph, Donald Trump could not help but lie.

Exulting over the summary findings of the Mueller Report — as interpreted and transmitted by his Attorney General William Barr — Trump declared that the investigation had found “no obstruction” and resulted in “complete and total exoneration.” But according to Mueller’s own words, that boast is utterly false, in particular with respect to a conspiracy to obstruct justice.

To quote directly from Barr’s memorandum to Congress, “the Special Counsel states that ‘while this report does not conclude that the President committed a crime, it also does not exonerate him.’”

Exactly what that partially-quoted sentence means remains to be seen — assuming that someday, the Justice Department or the Congress will disclose the rest of Mueller’s findings and evidence. Why was Robert Mueller unable to clear the president of obstruction of justice — the crime that led to the ouster of Richard Nixon — and how did he approach that question?

What we do know is that the ultimate decision on whether to charge Trump with obstruction was left to Barr and Rod Rosenstein, the deputy attorney general. But that result undermines the entire purpose of the Special Counsel Act, which was to ensure that conflicted Justice Department officials didn’t make prosecution decisions about the president who appointed them.

Barr’s own problem was far worse than the ordinary conflict contemplated by the act, since he was selected for his job by the president specifically because, not long before his appointment, he said that Trump as president should not be prosecuted for obstruction. More than a few observers thought Barr should be disqualified as attorney general for that expression of bias.

Barr’s letter says that his decision on an obstruction charge was not based on his views about the presidency, but on Mueller’s finding that Trump did not commit the underlying crime of conspiring with the Russians to interfere with the 2016 election. The absence of sufficient evidence to charge on obstruction thus “bears on the President’s intent with respect to obstruction.” According to Barr, the Mueller report “identifies no actions that, in our judgment, constitute obstructive conduct, had a nexus to a pending or contemplated proceeding, and were done with corrupt intent…”

But there are huge holes in that justification. Without interviewing the president, it seems impossible for either Mueller or Barr to determine his intent. And the president, despite his personal promise to submit to a Mueller interview, instead evaded it. And that leaves aside the glaring fact that the president himself declared he fired James Comey as FBI director to kill the Russia probe — a declaration of corrupt intent uttered in public more than once.

Even more telling is Barr’s attempt to brush aside Trump’s dangling of a pardon before Paul Manafort and other defendants. That hinted favor appears to have had an enormous impact on the Russia investigation, because the Office of Special Counsel indicated as much in its sentencing memorandum on Manafort.

The Mueller prosecutors accused Manafort of violating his cooperation agreement with them by lying about an event of utmost importance to the special counsel’s investigation: namely, his meeting with Konstantin Kilimnik, identified as a Russian government asset by the FBI, where he gave Kilimnik 75 pages of highly detailed Trump campaign polling data. Manafort also tried to conceal several meetings with Kilimnik to discuss the lifting of economic sanctions on Russia that were imposed after Putin’s invasion of Crimea.

In short, Manafort’s lies to Mueller — motivated by his hopes of a pardon that were encouraged by Trump and his lawyers — may have erected a stonewall even the special counsel could not surmount.

Americans need to know why, despite the activities of Manafort and so many other contacts between the Russians and the Trump campaign, the investigation “did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities.”

That question cannot be answered without release of the full text of the Mueller Report and its underlying evidence. Bill Barr’s spin is far from sufficient.